From the Guidelines
The recommended workup for a patient suspected of having an abdominal aortic aneurysm (AAA) begins with abdominal ultrasound as the initial screening test due to its high sensitivity, low cost, and lack of radiation exposure. If an AAA is detected or strongly suspected, a CT angiogram with contrast should be performed to confirm the diagnosis, determine the exact size and location of the aneurysm, and assess for complications such as rupture or dissection. Management depends primarily on aneurysm size. For small AAAs (<5.0 cm in men, <4.5 cm in women), surveillance with regular ultrasound or CT imaging is recommended every 6-12 months, along with cardiovascular risk factor modification including smoking cessation, blood pressure control (target <130/80 mmHg), statin therapy, and antiplatelet medication 1.
Key Considerations
- The size threshold for elective repair is ≥5.5 cm in men and ≥5.0 cm in women 1.
- For larger AAAs or those with rapid growth (>0.5 cm in 6 months), surgical intervention is indicated.
- The two main surgical options are open surgical repair and endovascular aneurysm repair (EVAR), with the choice depending on patient anatomy, surgical risk factors, and life expectancy.
- EVAR is generally preferred for higher-risk patients as it has lower perioperative mortality, while open repair may be more durable long-term.
Surveillance and Follow-Up
- Patients with small AAAs should undergo regular surveillance with ultrasound or CT imaging every 6-12 months to monitor for growth and development of complications.
- Following repair, patients need lifelong surveillance with imaging to monitor for complications or development of new aneurysms 1.
- The American College of Radiology Appropriateness Criteria recommend CT angiography as the primary imaging modality for both preoperative planning and follow-up after repair 1.
Risk Factor Modification
- Cardiovascular risk factor modification is crucial in the management of AAA, including smoking cessation, blood pressure control, statin therapy, and antiplatelet medication 1.
- Patients with symptomatic AAAs (presenting with abdominal or back pain) or ruptured AAAs require immediate surgical intervention regardless of size.
From the Research
Recommended Workup for Abdominal Aortic Aneurysm (AAA)
The workup for AAA involves several imaging modalities to diagnose and monitor the condition. The key recommendations are:
- Ultrasound is the mainstay imaging modality for AAA screening and surveillance 2, 3.
- Contrast-enhanced CT angiography is currently considered the gold standard for preoperative imaging and image-based treatment planning in AAA repair 2, 3.
- Non-contrast MR angiography allows for accurate monitoring of aortic diameters in AAA patients 2.
- Measurement of aortic diameters is more accurate with 3D-CT/MRI compared to ultrasound 2, 4.
Importance of Accurate Measurement
Accurate and reproducible measurement of AAA size is crucial for patient management. The use of non-standardized measurement techniques can lead to incorrect classification of AAAs and errors in quantification of aneurysm enlargement rate 4.
- Multiplanar reformation (MPR) strategy is recommended for accurate measurement of AAA size 4.
- Discrepancies between clinical and reference diameters can have significant clinical ramifications, including misclassification of AAAs with respect to the common repair threshold of 5.5 cm 4.
Management of AAA
The management of AAA involves screening, surveillance, and treatment.
- Screening for AAA can aid in the early diagnosis and treatment of the disease, reducing complications and death amongst those affected 5.
- Endovascular aortic aneurysm repair (EVAR) is an established approach to treating abdominal aortic aneurysms, with various technological developments and solutions available for complex cases 6.
- The choice of treatment depends on the individual patient's condition, and understanding the currently available evidence for each option is essential to select the most suitable procedure 6.